Trace into makes source code screen go blank

Question

Trying to walk through this code segment on inner classes from Bruce Eckel's Thinking in Java. When I hit trace into (F7), the trace into starts (as I can watch the sequence in Context Browser, but I the source code window goes blank with just a highlighted 1st line with no code shown.
If I remove the extends to the interface and abstract class and comment out the respective casts and return values, the problem disappears. So, it must be related to the extending with inner classes.
Anyone seen this before??? try it.
abstract class Contents {
abstract public int value();
interface Destination {
String readLabel();
public class Parcel10 {
private static class PContents extends Contents {
private int i = 11;
public int value() { return i; }
protected static class PDestination implements Destination {
private String label;
private PDestination(String whereTo) {
label = whereTo;
public String readLabel() { return label; }
public static Destination dest(String s) {
return new PDestination(s);
public static Contents cont() {
return new PContents();
public static void main(String[] args) {
Contents c = cont();
Destination d = dest("Tanzania");
} ///:~

Answer 1

Chris,
I just tried your code using JDeveloper 3.2 - I can not reproduce your results.
What I did was:
-Created a Class named Parcel10,
-Pasted your code below into it (everything except package statement).
-Set a breakpoint on main
-Right clicked on Parcel10 and selected Debug
-Stepped into the code for all the steps and nothing odd happens.
If you can produce a simple reproduce case,
then we can look into this further.
Thanks,
-John
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